Thread forming chaser and supporting means therefor



Sept. 21, 1937. BAR K 2,693,50

THREAD FORMING CHASER AND SUPPORTING MEANS THEREFOR Filed July 30, 1936 ATTORNEY.

Patented Sept. 21, 1937 FORMING CHASER AND SUPPORT- ING MEANS THEREFOR THREAD PATENT OFFICE John sl BartekuRochester, N. assignor to Consolidated Machine Tool Corporation, Rochester, N. Y., a corporation of Delaware Application July 30,1936, Serial No. 93,437

, '4 Claims.

invention relates to a thread forming chaser and supporting means therefor, and has for its "object to provide a simple and practical form of chaser of short life and minimum cost, for use where a small volume of work is required,

after which the chaser may be discarded.

A further object of the invention is to provide a structure involving a relatively thinchaser with a small-amount of stock, which can'be quickly and rigidly secured to its support.

Still an additional object of the invention isto afford a chaser of the character referred to, in

connection with a supporting block that is remov able from a die head to permit the use of different sizes'or styles of chasers, the chaser being;

secured to its support in such manner asto impart the necessary helical angle to the thread that is cut, the cutting elements on the chaser being disposed at right angles to its longitudinal'axis.

To thesepand other ends, the invention consists in"the'construction and arrangement of parts that will appear clearly from the following description when read in conjunction with the accompanying drawing, the novel features being pointed out in the claims following the specification.

In the drawing:

Fig. 1 is a side elevation, partially in section, of a die head showing the general arrangement of removable supporting block, with the chaser removed therefrom;

Fig. 2 is an end elevation of the die head and supporting blocks, with the Chasers clamped in position;

Fig. 3 is an enlarged end elevation, similar to Fig. 2, of one of the supporting blocks with the chaser clamped therein;

Fig, 4 is a bottom plan view of the structure illustrated in Fig. 3;

Fig. 5 is a longitudinal vertical sectional view taken centrally of the structure shown in Fig. 3,

and

Fig. 6 is a plan view of the chaser looking at its rear edge.

Referring more particularly to the drawing, in which like reference characters refer to the same parts throughout the several views, I designates in general the die head which is slotted at 2 to receive the several chaser supporting blocks 3 which are operated inwardly and outwardly by cam members 4, being positioned inwardly during the threading operation and actuated outwardly at the endthereof to release the work, as usual in this type of construction. The structure thus far described is of known type, and forms no part of'the present invention, which has to do with the form of the chaser and the means for mounting it on the supporting block 3.

The chaser; which constitutes part of the present invention, is designated generally at 5, and is 5 of relatively thin stock, as appears in Figs. 3 and 4, the supporting block 3 being slottedto receive the chaser.

The cutting elements on the chaser are disposed at right angles to the longitudinal axis of 1 the chaser, andto obtain the required helical angle of the thread produced on the work, the slot in the supporting block 3 is arranged at an angle to the longitudinal axis of the die head, and of the supporting block, as shown inFig. 4, so that the position of the *chaser in the supporting block imparts the necessary helical angle'to the thread produced. c

The rear end of the chaser is inclined at 6 and abuts against a similarly inclined surface at the base of'the slot in thesupporting block, such inclined surface being formed on an inserted member or filler piece 1 positioned in the slot in the block and permanently attached thereto by a pin 8.

The outer end of the chaser is recessed at its rear edge, said recess being defined by a circularly curved side wall 9, and a curved undercut end wall or base H3, which surfaces contact with cooperating surfaces of a clamping screw, designated generally at H and attachable to the supporting block. The supporting block is suitably threaded to receive said screw II and recessed to receive the head of the screw. One side of the screw headengages the aforesaid recess in the chaser, the rear face of the head of the screw being undercut and curved to engage the cooperating undercut surface it on the chaser, while the side of the head of the screw coincides with the curved side 9 of the recess on the chaser. 40

It will be seen that the screw, when in clamping position, holds the outer end of the chaser against either endwise or lateral movement with reference to the supporting block, dueto the cooperating undercut surfaces on the chaser and clamping 5 screw while the opposite end of the chaser is held against any lateral movement by reason of its inclined surface 6 abutting tightly against the correspondingly inclined surface on the inserted piece 1 of the supporting block.

This type of construction is intended primarily for short runs or small volume of work, and when the chaser is dull or unfit for further operation, it is removed and a fresh one clamped in position. It i will be understood that each chaser cuts a given helical angle, and if a different angle or different size work is involved, the supporting block is removed from the die head and another block inserted, in which the chaser is set at the required angle thereon.

While the invention has been described with reference to a certain structural embodiment, it is not confined to the details and arrangement herein shown, and this application is intended to cover such other modifications or departures as may come within the purposes of the improvement or the scope of the following claims.

I claim:

1. The combination with a relatively thin chaser, of a support therefor having a slot to re ceive the chaser, the latter having an inclined end, an inclined wall at the base of said slot of the support to engage said inclined end of the chaser, the outer end of the chaser having a recess at its rear edge, the base of said recess being defined by an undercut surface, and a clamping screw attachable to the support and having a head engaging said recess in the chaser, the rear face of said screw head being undercut and cooperating with said undercut surface of the recess in the chaser.

2. The combination with a relatively thin chaser, of a support therefor having a slot to receive the chaser, a separate filler block permanently secured in said slot and having an inclined surface against which the inner end of the chaser abuts, said inner end of the chaser being correspondingly inclined, the outer end of the chaser having a recess at its rear edge, the side of said recess being defined by a circular surface and the base of said recess being defined by a curved undercut surface, and a clamping screw attachable to the support having a head with a curved undercut rear face which cooperates with said curved undercut surface of the recess of the chaser, the side of the head of the screw cooperating with said circular side surface of the recess.

3. The combination with a die head and a removable supporting block, of a relatively thin chaser having an inclined end, the supporting block having a slot therein to receive said chaser and an inclined wall at the base of said slot cooperating with said inclined end of the chaser, the outer end of the chaser having a recess at its rear edge, said recess being defined by a circular side wall and an undercut curved base, and a clamping screw attachable to the supporting block and having a head with an undercut curved rear face engaging said undercut base of the recess in the chaser while the side of the screw head engages the circular side of said recess, the slot in the supporting block and the chaser being arranged at an angle to the longitudinal axis of the supporting block and die head.

4. The combination with a relatively thin chaser, of a support having a. slot to receive the chaser, the latter having an inclined end, an inclined wall at the base of said slot of the support to engage said inclined end of the chaser, said support having a threaded opening to receive a clamping screw and an enlarged circular opening at the outer end of said thread-ed opening to receive the head of the clamping screw, said enlarged circular opening intersecting said slot in the support, the outer end of the chaser having a curved recess at its rear edge which coincides with said circular opening in the support when the chaser is in operative position, and a clamping screw engageable in said threaded opening and having a circular head positionable in said circular opening of the support and said curved recess of the chaser, said head overlying the rear part of the chaser at the base of said curved recess and interlocking therewith to prevent movement of the chaser in the slot.

JOHN S. BARTEK. 

